Intracellular polarity protein PAR-1 regulates extracellular laminin assembly by regulating the dystroglycan complex |
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Authors: | Maki Masuda-Hirata Atsushi Suzuki Yoshiko Amano Kazunari Yamashita Mariko Ide Tomoyuki Yamanaka Michihiro Sakai Michihiro Imamura Shigeo Ohno |
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Affiliation: | Department of Molecular Biology, Yokohama City University Graduate School of Medical Science, 3-9 Fuku-ura, Kanazawa-ku, Yokohama 236-0004, Japan; Department of Anesthesiology, Yokohama City University Graduate School of Medical Science, 3-9 Fuku-ura, Kanazawa-ku, Yokohama 236-0004, Japan; Department of Molecular Therapy, National Institute of Neuroscience, NCNP, 4-1-1 Ogawahigashi-cho, Kodaira, Tokyo 187-8502, Japan |
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Abstract: | Cell polarity depends on extrinsic spatial cues and intrinsic polarity proteins including PAR-aPKC proteins. In mammalian epithelial cells, cell–cell contacts provide spatial cues that activate the aPKC-PAR-3-PAR-6 complex to establish the landmark of the initial cellular asymmetry. PAR-1, a downstream target of the aPKC-PAR-3-PAR-6 complex, mediates further development of the apical and basolateral membrane domains. However, the relationships between the PAR-aPKC proteins and other extrinsic spatial cues provided by the extracellular matrix (ECM) remain unclear. Here, we show that PAR-1 colocalizes with laminin receptors and is required for the assembly of extracellular laminin on the basal surface of epithelial cells. Furthermore, PAR-1 regulates the basolateral localization of the dystroglycan (DG) complex, one of the laminin receptors essential for basement membrane formation. We also show that PAR-1 interacts with the DG complex and is required for the formation of a functional DG complex. These results reveal the presence of a novel inside-out pathway in which an intracellular polarity protein regulates the ECM organization required for epithelial cell polarity and tissue morphogenesis. |
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